Mobile devices today often support multiple radio access technologies (RATs), such as Wi-Fi and mobile networks (such as 2G/3G/4G). Mobile devices are many times on their own in finding the network and network type that best suits the actual demand. Hence, mobile devices often have a choice of attaching to large cells of mobile networks or to small cells in hot spots. Nowadays, the large cells are usually the macro cells of mobile networks and the small cells are mostly Wi-Fi access points, but 3G/4G pico and femto cells have been also installed in growing numbers recently.
Hence, it is desired that mobile networks are made to work smoothly together with network technologies for the small cells, e.g. networks operating in non-licensed bands, such as Wi-Fi. One way to achieve such interworking is a so called Inter Radio Access Technology (IRAT) handover process. This process splits the tasks between the network and mobile devices and can reduce processor and battery limitations of mobile devices.
In order to keep requirements on mobile devices low, it is desired that the measurement and reporting duties of mobile devices are kept low. However, as new technologies and operating frequency bands are introduced, any monitoring and reporting by the mobile device is only likely to increase, which increases power usage and decreases battery life.
WO 2009/108723 presents a detecting base station which detects a wireless communication device by intercepting an uplink communication signal intended for an originating base station. In response to the detection of the wireless communication device, the detecting base station sends a message to the core network. The detecting base station includes a mobile communication device detector configured to intercept the uplink communication signal transmitted from the wireless communication device to the originating base station of a communication network. A network interface within the detecting base station is configured to send a device proximity message to the communication network where the device proximity message is based on the proximity of the wireless communication device to the detecting base station. The device proximity message may be a handoff request, distance, or other information that is derived or otherwise related to the intercepted uplink communication signal.
However, such a solution requires the detecting base station to intercept, which requires decoding of signals. Such decoding of signals is not only resource demanding but also dependent on the communication technology used.
It would be of great benefit if there was a way to detect uplink traffic for identification of the source device without the need to decode the uplink traffic signal.